Add JSON_DELETE_DEPRECATED_FUNCTIONS to delete the deprecated functions (#5755)

* Add JSON_DELETE_DEPRECATED_FUNCTIONS to delete the deprecated functions

Defining JSON_DELETE_DEPRECATED_FUNCTIONS to 1 (or the CMake option
JSON_DeleteDeprecatedFunctions) declares every deprecated function as
deleted instead of deprecated, so that code that is not ready for 4.0.0
no longer compiles. A deleted function still takes part in overload
resolution, so from_*(ptr, len) cannot silently bind len to the strict
parameter of from_*(InputType&&, bool); the roadmap now plans to keep
these overloads deleted in 4.0.0 instead of removing them.

The legacy discarded-value comparison is left to its own macro.

Also update the 4.0 roadmap: add JSON_DISABLE_TUPLE_REFERENCE_CONVERSION
and JSON_DELETE_DEPRECATED_FUNCTIONS to the macro table, add the
from_bjdata/from_bon8 (ptr, len) overloads to the deprecated functions,
document the macro in the migration guide, and fix the docs style check
findings (example titles, missing docset entry for JSON_STRICT_BINARY_UTF8).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Declare each deprecated function once and guard only its body

Instead of repeating every deprecated declaration in an
#if JSON_DELETE_DEPRECATED_FUNCTIONS branch, keep one declaration
(with its deprecation attribute) and switch only between "= delete;"
and the function body. Suggested by @gregmarr in the review.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
This commit is contained in:
Niels Lohmann
2026-10-04 22:11:34 +02:00
committed by GitHub
parent c5a7a4b46d
commit 23d3b373e1
30 changed files with 755 additions and 15 deletions
+24
View File
@@ -81,9 +81,13 @@ class json_pointer
/// @sa https://json.nlohmann.me/api/json_pointer/operator_string_t/
JSON_HEDLEY_DEPRECATED_FOR(3.11.0, to_string())
operator string_t() const
#if JSON_DELETE_DEPRECATED_FUNCTIONS
= delete;
#else
{
return to_string();
}
#endif
#ifndef JSON_NO_IO
/// @brief write string representation of the JSON pointer to stream
@@ -1022,9 +1026,13 @@ class json_pointer
/// @sa https://json.nlohmann.me/api/json_pointer/operator_eq/
JSON_HEDLEY_DEPRECATED_FOR(3.11.2, operator==(json_pointer))
bool operator==(const string_t& rhs) const
#if JSON_DELETE_DEPRECATED_FUNCTIONS
= delete;
#else
{
return *this == json_pointer(rhs);
}
#endif
/// @brief 3-way compares two JSON pointers
template<typename RefStringTypeRhs>
@@ -1102,18 +1110,26 @@ template<typename RefStringTypeLhs,
JSON_HEDLEY_DEPRECATED_FOR(3.11.2, operator==(json_pointer, json_pointer))
inline bool operator==(const json_pointer<RefStringTypeLhs>& lhs,
const StringType& rhs)
#if JSON_DELETE_DEPRECATED_FUNCTIONS
= delete;
#else
{
return lhs == json_pointer<RefStringTypeLhs>(rhs);
}
#endif
template<typename RefStringTypeRhs,
typename StringType = typename json_pointer<RefStringTypeRhs>::string_t>
JSON_HEDLEY_DEPRECATED_FOR(3.11.2, operator==(json_pointer, json_pointer))
inline bool operator==(const StringType& lhs,
const json_pointer<RefStringTypeRhs>& rhs)
#if JSON_DELETE_DEPRECATED_FUNCTIONS
= delete;
#else
{
return json_pointer<RefStringTypeRhs>(lhs) == rhs;
}
#endif
template<typename RefStringTypeLhs, typename RefStringTypeRhs>
inline bool operator!=(const json_pointer<RefStringTypeLhs>& lhs,
@@ -1127,18 +1143,26 @@ template<typename RefStringTypeLhs,
JSON_HEDLEY_DEPRECATED_FOR(3.11.2, operator!=(json_pointer, json_pointer))
inline bool operator!=(const json_pointer<RefStringTypeLhs>& lhs,
const StringType& rhs)
#if JSON_DELETE_DEPRECATED_FUNCTIONS
= delete;
#else
{
return !(lhs == rhs);
}
#endif
template<typename RefStringTypeRhs,
typename StringType = typename json_pointer<RefStringTypeRhs>::string_t>
JSON_HEDLEY_DEPRECATED_FOR(3.11.2, operator!=(json_pointer, json_pointer))
inline bool operator!=(const StringType& lhs,
const json_pointer<RefStringTypeRhs>& rhs)
#if JSON_DELETE_DEPRECATED_FUNCTIONS
= delete;
#else
{
return !(lhs == rhs);
}
#endif
template<typename RefStringTypeLhs, typename RefStringTypeRhs>
inline bool operator<(const json_pointer<RefStringTypeLhs>& lhs,